Process for breaking petroleum emulsions



PROCESS FOR BREAKING PETROLEUM EMULIONS Melvin De Groote, University City, Mo., assignor to Petrolite Corporation, a corporation of Delaware N Drawing. Application January 21, 1052, Serial No. 267,513

11 Claims. (Cl. 252-340) This invention relates to processes or procedures particularly adapted for preventing, breaking or resolving emulsions of the water-in-oil type, and particularly petroleum emulsions.

Complementary to the above aspect of my invention is my companion invention concerned with the new chemical products or compounds used as the demulsifying agents in said aforementioned processes or procedures, as well as the application of such chemical compounds, products and the like, in various other arts and industries, along with the method for manufacturing said new chemical products or compounds which are of outstanding value in demulsification. See my co-pending application, Serial No. 267,514, filed January 21, 1952.

My invention provides an economical and rapid process for resolving petroleum emulsions of the water-in-oil type, that are commonly referred to as cut oil, roily oil," emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion.

It also provides an economical and rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification under the conditions just mentioned are of significant value in relmovinslg impurities, particularly inorganic salts, from pipe- The demulsifying agents employed in the present process are fractional esters obtained from a polycarboxy acid or the equivalent and oxypropylation derivatives in turn derived from the oxypropylation of glycols having the general formula wherein R represents an alkyl radical containing at least 5 and not more than 18 carbon atoms in its chain, and R" represents an alkyl radical containing not more than 18 carbon atoms. Such glycol of the kind described is treated with propylene oxide so that the molecular weight based on the hydroxyl value is within the range of 1000 to approximately 7000. Such oxypropylated derivatives are invariably xylene-soluble and water-insoluble. When the molecular weight, based on the hydroxyl value, is in the neighborhood of 1000 or thereabouts, the oxypropylated product is almost invariably kerosene-soluble. In fact, depending on the particular glycol subjected to oxypropylation the product may become kerosene-soluble at a lower range, for instance, at a range as low as 700 or 800 molecular weight. Such products can be obtained wherein one of the alkyl radicals has more than 5 carbon atoms provided the other radical has at least 5 or more and with the final proviso that the diol be water-insoluble.

These glycols which are subjected to oxypropylation prior to esterification may be obtained by well-known methods, for example, by the sodium reduction of the esters of the higher fatty acids followed by hydrogenation of the resulting acyloins to glycols. See U. S. Patent No. 2,079,403, dated May 4, 1937, to Hansley.

My preference, as noted elsewhere, is to have both alkyl radicals the same and having 7 to 18 carbon atoms. However, as previously pointed out the radicals may have 7 to 18 carbon atoms and not necessarily be the same radical, for instance, one could have 7 carbon atoms and still, kerosene-soluble.

the other 18 carbon atoms. Typical examples where R and R are the same are the following:

C11H23CHOHCHOH-C11H23 (Diundecyl ethyleneglyeol) C9H19CHOHCHOHC9H19 (Dinonyl ethyleneglycol) C'1H15CHOHCHOHC7H15 (Diheptyl ethyleneglycol) More specifically, the glycols which I prefer to use are those having the general formula wherein R and R represent the same saturated unsubstituted alkyl groups having straight chains containing from 7 to 18 carbon atoms.

For convenience, then, the oxypropylated derivative of the glycol may be indicated thus:

with the proviso that n and n represent whole numbers which, when added together, equal a sum varying from 15 to 80 and the acidic ester obtained by reaction with the polycarboxy acid may be indicated thus:

in which the characters have their previous significance, and n" is a whole number not over 2, and R is the radical of the polycarboxy acid and preferably free from any radicals having more than 8 uninterrupted carbon atoms in a single group, and with the further proviso that the parent diol, prior to esterification, be preferably xylene-soluble, and better The diols herein employed as raw materials are water-insoluble.

Attention is directed to U. S. Patent No. 2,562,878, dated August 7, 1951, in which there is described, among other things, a process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of an esterification product of a dicarboxylic acid and a polyalkylene glycol, in which the ratio of equivalents of polybasic acid to equivalents of polyalkylene glycol is in the range of 0.5 to 2.0, in which the alkylene group has from 2 to 3 carbon atoms, and in which the molecular weight of the product is between 1,500 to 4,000.

In the instant case the initial starting materials, i. e., glycols having the general formula in which R and R have their prior significance, are water-insoluble. Numerous water-insoluble compounds susceptible to oxyalkylation, and particularly, to oxyethylation, have been oxyethylated so as to produce eifective surface-active agents, which, in some instances at least, also have had at least modest demulsifying property. Reference is made to similar monomeric compounds having a hydrophobe group containing, for example, 8 to 32 carbon atoms and a reactive hydrogen atom, such as the usual acids, alcohols, alkylated phenols, amines, amides, etc. In such instances, invariably the approach was to introduce a counter-balancing effect by means of the addition of a hydrophile group, particularly ethylene oxide, or, in some instances, glycide, or perhaps a mixture of both hydrophile groups and hydrophobe groups, as, for example, in the introduction of propylene oxide along with ethylene oxide. On another type of material a polymeric material, such as resin, has been subjected to reaction Patented Nov. 30, 1954:

in which R and-R havextheir'rprevious: significance, happens to be one .caseoia.suitablecompound. On the other hand, somewhat closely related compounds, for instance,:alkylesters; ,ofvdihydroxylated tcomponndszzsnch as dihydroxystearic acid, do notiseenrito yicldtanalogous: derivatives of nearly .the-efiectiveness of.the herein described glycols. This is'true also of a large number of other dihyroxylatedcompounds-z-wwhich :are essentially: water-insoluble and whicl1--have-a;to1al.1o '8 to 32 carbon.-

atoms in the compound. Thenreasomor reasons .-for=. this difierenceis merely a:.matter; ofifspeculationcn. These glycols are comparativelywexpensive: and; obviously if cheaper, dihydroxylated compounds ,of approximately the same general characteristics would serve nothing would be gained by the :employment of a more-:expensive raw material.

Exhaustive voxypropylationrenders-a water-soluble ma,- terial water-insolublem. Similarly, "it renders;ra:.kerosene-.- insoluble material kerosene-soluble; for instance, reference has been made to the fact that: this is true, for example, using--polypropyleneglycol 2,000: Actually, it is true with polypropyleneglycol,havinglower molecular weights than 2,000. These materials are obtained by the oxypropylation of a water-soluble kerosene-insoluble material; .i. ;e.,..either. water or .propyleneglycob Just. why certain different materials which are waterinsoluble to start with, and whichrpr,esumably;* are I611:- dered more water-insoluble by exhaustive oxypropylation (if such expression as more water-insoluble has significance) can be converted into a'valuble surface-active agent, and particularly a valuable demulsifying agent, by reaction with a polycarboxy acid which does not particularly affect.- .the zzsoliibilityone :way; 201: -the..'otlrer--- dgpendinguupon the selection-of the =acid'is-:unexplaiiw a e The new: products dterein described; are usefiulrforra:

number of purposesz-"othernthan resolution-of::petroleum:1 emulsions. See my co-pending :applicatiom-rSerial::Nor 267,514;- filedtzJanuary' 2F, .1952.

For. -convenience,.- what: is: said :hereinaftn Will bewdi-i. vided into=four parts:

Part1 will-be concerned withitheroxypropylated deriva-.. tivesi. e.,- diolsof: the:previously described-:tglycols;

Part2 will'be concernednwithrthe preparation ofresters from the aforementioned' di'o1s: or-w'dilliydroxylated xcome; pounds;

Part 3 willqbez-concerned with'tthe'natureaofntheprom ucts obtained- .by-oxypropylatio'n rinr light: of .therfact: that certain side reactions invariably and inevitablyoccura and Part .4 -will: be concerned :iwitlriithecuse. sofa Cthfif'CStfiTS obtained as described:.in-.--.Part"t2 afor. the 'resolu'tionzzoi petroleum emulsions of the water-in-oil type.

PART 1 of catalyst; and the kinclr'ofcatalyst ibut also in regard J. to:the time of reaction, temperature of reaction, speed j of reaction, pressure during reaction, etc." For instance, oxyalkylatio'ns can-be condu'cted at temperaturesauptptot approx1mately2O0C;, with pressures in" about the s m range up to about 200 pounds per, square inch. They can be conducted, also, at temperatures approximating the boiling point of wateror slightly above, as, for example, to C. Under such circumstances the pressure will be less than 30 pounds per square inch unless some special procedure'tisl employed as is sometimes the case, to wit, keeping an atmosphere of inert gas such as nitrogen in the 'vessel during-the reaction. Such low-temperature-low reaction-- rate oxypropylations have -been described .very.completely in U. S..Patent. No: 2,448,664 ito,;H'.R-." Fife -et' al;, dated September 7 1948. L'ow-temperature-low-pressure-- oxypropylations are particularly desirable wherepthe compound being subjected to oxypropyla'tioncontain one,.,two, or three points of reaction only, such as monohydric alcohols, glycols and triols.

Since low pressure low temperature low reaction speed oxypropylations require considerable time,.for.,instance,- 1 to 7 days of- '24: hours-each to-'-complete;the reaction, they 1 are conducted as, a rule, ,whetheraod-a laboratory scale, pilot-plant=scale,--or-large scale so as to operate automatically. Theprior figure-of-seven -days' applies especially to large-scale-operations-involving excessive -oxypropylatioh. I have used 'conventidnalequipment with twoadded automatidfe'atures:

((1') A solenoid-controlled valvewhich shuts off the propylene oxide in event that thetemperature gets outside a predetermined and set-rangq-fo'n instance 95 to 1205 C1; orv?"to;135 CI; and

(12) Another solenoid walve -which shuts'oif the-pro-. pylene OXidC (0l f0'I that matter ethylene oxide if it is being used) if the pressure.gets: beyond alpredeterm-ined rangeysuch-asv-Zf Eto 35-'pounds; Otherwise, the-equipment is substantially the -same"as-is commonlyemployed forthis purpose where the pressure-of reaction ishigher, speed-ofreaction-is-.-higher, and time of-reaction -is much shorter.'.' In suchrinstances I suchautomatic controlsare.- not-v necessarily ausedr.

Thus,.in-:preparing the variousexamples I have found it-part-icularly' advantageous: to use. laboratory equipment or. pilotwplant' equipmentewhichi is designed. to permit: continuous;-'oxyalkylation;--whether =it-be oxypropylation or' -oxyethylation-.' With certain-v obvious changes the equipment canebe '-used i also-:.topermitu oxyalkylation involving; the 51156;; ofiiglycidemwhere no pressure -is in volvfed, :except :the: avapor: ipressure :of r a solvent, if any which may have been used as a diluent.

As previously pointed :out; the 'cmethod :ofausing: propylenenoxiderisethe same sasnethylene=soxide This pointisvemphasizedronly forthetreason that theapparatus is sordesig'ned andrconstructedhs*toruse: either:.:oxide.-

The oxypropylation procedure employedinrthe prepa= ration of the oxyalkylated derivatives has been uniformly the same, particularly-tiiinlightwofifthe-fact that a continuous automatically-controlled procedure was employed. lrrsthist procedure'rtheaautoclaveawas a zconventionalfautoclave made of stainless: steehand having-r21. capacityiofi' approximately -l5 *gallons andawworking zpressureof one thousand pounds gauge ZPIQSSU'ITB. This pressure obviously is far beyond; any :requirement fas; -.far as propylene oxide goes, unless"therewisaa :reactionofiexplosiv'e violence involved :due -toz-accidentn T he. autoclave was-equipped with the ,conventionah devices: and ..r)penirtgs,-: such 1 as -the 1 variablerspeedastirner operating at: sp eeds' from :5 0 RE PI-M'; to- 500r-R1-s P: M.;. thermometer well Zandwthermocouple for mechanicali thermometer; emptying: outlet; 1- pressure gauge; manual ventrline; charge; hole for.- initial reactants; at least one connection.=for-introducing ltheialkylene oxide; such aspropyleneoxide or ethylene oxide,:..to) the bottomof the :autoclave; along uwith'nsuitable devices for-both cooling and-:heating theaautoclave; such .as -a.cooling jacket; and, preferably .coils& in additionthereto with l the jacket :so--arrangedthat :itPisisuitable' for heating with steamror cooling *withiwaterand further equipped with electrical heating devices-n Snchiautoclavesare,-of course; in essencesmall-scale-:replicas of the-rusual conventional autoclave .rused in.:oxyalkylationrproceduress In some: instances, in; exploratory preparations an.-autoclave having-7 a smaller capacity; for instan :,e,-..-approximately.3% liters" in-one .case, andraboutrl fingallons in. another.-;-case,-. was used...

C ntinuous operation 011--Substantially;continuous -op eration, was .achievedby the..us,e,,of,, a .separatecontainer to hold ,the alkylfifne oxide-tbeing employed,..particularly propylene oxide. In conjunction with the smaller autoclaves the container consists essentially of a laboratory bomb having a capacity of about one-half gallon, or somewhat in excess thereof. In some instances a larger bomb was used, to wit, one having a capacity of about one gallon. This bomb was equipped, also, with an inlet for charging, and an eductor tube going to the bottom of the container so as to permit discharging of alkylene oxide in the liquid phase to the autoclave. A bomb having a capacity of about 60 pounds was used in connection with the -gallon autoclave. Other conventional equipment consists, of course, of the rupture disc, pressure gauge, sight feed glass, thermometer connection for nitrogen for pressuring bomb, etc. The bomb was placed on a scale during use. The connections between the bomb and the autoclave were flexible stainless steel hose or tubing so that continuous weighings could be made without breaking or making any connections. This applies also to the nitrogen line, which was used to pressure the bomb reservoir. To the extent that it was required any other usual conventional procedure or addition which provided greater safety was used, of course, such as safety glass, protective screens, etc.

Attention is directed again to what has been said previously in regard to automatic controls, which shut oil the propylene oxide in event temperature of reaction passes out of the predetermined range, or if pressure in the autoclave passes out of predetermined range.

With this particular arrangement practically all oxypropylations become uniform in that the reaction temperature was held within a few degrees of any selected point, for instance, if 130 C. was selected as the operating temperature the maximum point would be at the most 135 C. or 138 C. and the lower point would be 125 C. or possibly 128 C. Similarly, the pressure was held at approximately pounds or less within a 5-pound variation one way or the other, but might drop to practically zero, especially where no solvent such as xylene is employed. The speed of reaction was comparatively slow under such conditions as compared with oxyalkyla' tions at 200 C. Numerous oxypropylations have been conducted in which the time varied from one day (24 hours) up to three days (72 hours), for completion of the final member of a series. In some instances the reaction involving the instant reactants may take place in considerably less time, i. e., 24 hours or less, as far as a partial oxypropylation is concerned. The minimum time recorded was about a 1 /2 hour period in a single step. Reactions indicated as being complete in 8 /2 hours may have been complete in a lesser period of time in light of the automatic equipment employed. This applies also where the reactions were complete in a shorter period of time, for instance, 2 to 5 hours. In the addition of propylene oxide in the autoclave equipment as far as possible the valves were set so all the propylene oxide if fed continuously, would be added at a rate so that the predetermined amount would react within the 5 hours of an 8-hour period, or two-thirds of any shorter period. This meant that if the reaction was interrupted automatically for a period of time for pressure to drop or temperature to drop, the predetermined amount of oxide would still be added in most instances well within the predetermined time period. Sometimes where the addition was a comparatively small amount in a 5-hour period there would be an unquestionable speeding up of the reaction by simply repeating the examples and using 1 /2, 2, or 3 hours instead of 5 hours.

When operating at a comparatively high temperature. for instance, between 150 and 200 C., an unreacted alkylene oxide such as propylene oxide makes its presence felt in the increase in pressure, or the consistency of a higher pressure. However, at a low enough temperature it may happen that the propylene oxide goes in as a liquid. If so, and if it remains unreacted, there is, of course, an inherent danger and appropriate steps must be taken to safeguard against this possibility; if need be, a sample must be withdrawn and examined for unreacted propylene oxide. One obvious procedure, of course, is to oxypropylate at a modestly higher temperature, for instance, at 140 to 150 C. Unreacted oxide afiects determination of the acetyl or hydroxyl value of the hydroxylated compound obtained.

The higher the molecular weight of the compound, i. e., towards the latter stages of reaction, the longer the time required to add a given amount of oxide. One possible explanation is that the molecule, being larger, the opportunity for random reaction is decreased. Inversely, the lower the molecular weight the faster the reaction takes place. For this reason, sometimes at least, increasing the concentration of the catalyst does not appreciably speed up the reaction, particularly when the product subjected to oxyalkylation has a comparatively high molecular weight. However, as has been pointed out previously, operating at a low pressure and a low temperature, even in large scale operations as much as a week or ten days time may lapse to obtain some of the higher molecular weight derivatives from monohydric or dihydric materials. Side reactions are almost invariably a problem. See U. S. Patent No. 2,236,919, dated April 1, 1941.

In a number of operations the counterbalance scale or dial scale holding the propylene oxide bomb was so set that when the predetermined amount of propylene oxide had passed into the reaction, the scale movement through a time-operating device was set for either one to two hours so that reaction continued for one to three hours after the final addition of the last propylene oxide, and thereafter the operation was shut down. This particular device is particularly suitable for use on larger equipment than laboratory size autoclaves, to wit, on semi-pilot plant or pilot plant size equipment, as well as on large scale size equipment. This final stirring period is intended to avoid the presence of unreacted oxide.

In this sort of operation, of course, the temperature range was controlled automatically by either use of cooling water, steam, or electrical heat, so as to raise or lower the temperature. The pressuring of the propylene oxide into the reaction vessel also was automatic insofar that the feed stream was set for a slow, continuous run which was shut oil in case the pressure passed a predetermined point, as previously set out. All the points of design, construction, etc., were conventional including the gases, check valves and entire equipment. As far as I am aware at least two firms, and possibly three, specialize in autoclave equipment such as I have employed in the laboratory and are prepared to furnish equipment of this same kind. Similarly, pilot plant equipment is available. This'point is simply made as a precaution in the direction of safety. Oxyalkylations, particularly involving ethylene oxide, glycide, propylene oxide, etc., should not be conducted except in equipment specifically designed for the purpose.

Example 1a The starting material was diundecyl ethyleneglycol. The particular autoclave employed was one having a capacity of about 15 gallons or on the average of pounds of reaction mass. The speed of the stirrer could be varied from about to 350 R. P. M. 20 pounds of diundecyl ethyleneglycol were charged into the autoclave along with 2 pounds of finely pulverized caustic soda. No solvent was added in this particular run although on smaller runs small amounts of xylene have been added; for instance, about one-half as much xylene as substituted glycol. Needless to say, one could not only add xylene but, for that matter, any conventional solvent. Even if the glycol is not completely soluble in the selected solvent, it still produces a slurry that is sometimes more convenient to handle.

The reaction pot was flushed out with nitrogen, the autoclave was sealed and the automatic devices set for injecting 50 pounds of propylene oxide in about 2 hours. At the end of this time the stirring was continued for another half hour. The pressuring device was set for a maximum of 30 pounds per square inch, or slightly in excess thereof, perhaps as high as 33 pounds. Actually in the course of the reactions due to the presence of a generous amount of catalyst the reaction pressure never got over 15 to 20 pounds either at this particular stage or in any of the subsequent examples, 2a through 6u, inclusive. For this reason no further reference will be made to operating pressures in subsequent stages. Needless to say, when one sets the gauge for a maximum pressure the bulk of the reaction can take place, and probably does take place, at a lower pressure. The low pressure is the result, as a rule of (a) Activity of the reactant,

(b) Presence of a sizable amount of catalyst, (c) Elficient agitation, and,

(d) A fairly long time of reaction.

The. propylene oxide was-added.- :comparatively "slowly "and; more important,- the-selected:temperature;:although mod-L eratelyyhigherrthanzthe boiling porutnof :water; was-.not excessively .high; for-instance; in'rthis particularstage, andrins' fact ins-all subsequent stages, reaction took 2 place-- within-thewrangezof' 130?" to 1135" C. For this. reason no furthenreference will-be made in Examples 2a through 6a --to temperature of reaction."

At= thexcompletion of the reaction a samplewas. taken andwoxypropylation proceeded as in. Example 12a; following;

Examplela 64-pounds of- (116":168011011'1111288, identified as Example. la,-;preceding,uand .equivalenttto "17.8 pounds of the original glycol; 44.42.. poundszrof propylene oxide, and l.78 -rpoundss= .ofiscausticcsodaxwere permitted. "to remain inthe-Teactionwvessel'.. Without the. additionof any more catalyst',;25..pouncls-ofipropylene:oxide were added. The OXYPI'OPYIafiOIIiWaS.COndlIlCtd ll1"1h same manner as outlinedfin .Exarnple-t:la,-preceding. particularly with regard: to ,temperature'andpressure. The reaction time was slightly shorter; notwithstanding .a lower concentration:of:cata1yst.-' was probably dueto the fact that lessoxiderwas added The time required was two hours. At the enda-of athe reactiomperiodfpart of the reaction mass awas ;withdrawn as a 1 sample .i. and oxypropylation continuedmwith the remaindertnf the-reaction mass as described in Example 3a:fo1lowing..

Example 3a Example 4a 89 pounds of the reaction mass identified as Example 361,: preceding: and :equivalentxto" 12.90 pounds of 'the initialzglycol, 71.84 pounds: of propylene oxide; and. 1.29

8 poundscof- :caustic soda; WeI'e""Pfi1m11td TtO remain inrthe autoclave? Without adding 'anyx more': CatK1YSlITtlIl1SiII6-C actionmass: was:.'subjected tailfllll'hlJOXYPI'OPYIBfiOH-Zitfi the same manner-as in the preceding exampler?v 20*poundsl ofpropylene oxide were addediniz-a .4 /2' houn-pcriodr:

Conditions .asfar. :as temperature and pressure 'were' coma cerned were :the same -:as in precedin'g :exampleszv Attirecompletion ofrthe. reactionapartpfi the reaction-mass :was; withdrawntzas- :a sample wand oxypropyla-tion r conductedu furtheras describedirr Example 5a, following.

Example 5a 79 pounds of thexreaction mass:identified as Example- 4a, preceding. and equivalent 2 to 9.37 pounds: :ofw the". ini-: 1 tial glycol, 68.7 "poundsz ofpropylene.:.oxide;:.and 1.931 pound of causticmsodazwere permittedzto remainiinnthe autoclave. Without. adding .any morexcatalyst:this reacez tion-mass :was subjectecl' to further oxypropylationvinrthe. same manner'as in the'preceding examples: Conditione as far as temperature andpressure=Werewconcerned .were the same as before: Thetimenrequiredzto add. the oxide 1 was 6 hours-, due :in' part to'zthe.lowerrconcentration/of catalyst. At. the. .completion rof= :the; reactionupart of the reaction massawaswithdrawn-was: a samplezxandmthe: rewmainder subjected .to further oxypropylation 'as 'described' in Example 6a,:immediatelyfollowing;

Example' 6a- 60 pounds. of-the reactionxmass' identified-as Example 5 a, preceding iand equivalent :to '5 .4 pounds of" .the:..initial:. glycol, -54.06:ipounds.-of propylene oxide; and: .54 pound-1 of caustic soda were reacted with "20 poundsof propylene oxide. No additional catalystwas.added;. The'reactio'ma as far as temperature "and. pressurewere concernedgwas. the same asin the,preceding...examples;-. Thewtirne zrequired to addathe oxide-was comparatively lo'ng;.--.to 1 wit-,- F 8 /2 hours.-

In this .particular: .series rof: examples the -oxypropylan tion was stopped'rat this stagew In other: seriesnl :have'. continued the oxypropyla'tion 2 so thatn thetheoretical l molecular weight:was :approximate1y- 8,000 to 9,200,5and; the hydroxyl--rnoleculanweightswereapproximately :3 ,75 0, 1 or thereabouts: Other weights; of=course3 are obtainable-,-- using the. sameprocedure;

WhatisIsaidherei-nis presentedin :ta-bulanform in-..Table 1, immediately following, .with some added-'zinformation-as to molecular .weight and as: .to: solubility?ot the-reactionw product in lwateruxylene and kerosene.-

Table VI Composition before Compositionat end Max Max r I TIIHO' Ex. No. Hlgh High temp., Pres 1 ,molal 2 E? Theo molal Oxide. Cata- Hyd.. 0. y; gly'eol, 'f 3 M. W. glycol, amt., lyst, mol.

lbs. lbs. lbs; lbs: wt:

20 2. O 1, 295 20. 0 50. 0 2. 0 I 950 130-135 15-20 2% 17; 8 44. 42 1. 78 1, 820 17. 8 69: 42' l. 78 1, 340: 130-135 15-20 2 15. 8 61. 62 1. 58 2, 515 15. 8 91.62. 1. 58 1, 810 130-135 15-20 3 12. 9 74. 81 1. 29 3, 090 12. 9 94. 81 1. 29 2, 050 130-135 15-20 4% Examples 1a through 61; were prepared from diundecylethyleneglycol. Examples 7a through 12a wereprepared from dinonylethyleneglyeol. 7 Examples l3a.through*17a were prepared from diheptylethyleneglyeol; Examples 18:; through 22a were prepared from diheptadeeylethyleneglycolt- As far as solubility is concerned, all the products were water-insoluble at all stages, but were xylene-soluble; and in the higher stages of oxypropylation, for instance at a hydroxyl molecular weight of 2,000 or more, they were kerosene-soluble.

Ordinarily in the initial oxypropylation of a simple compound, such as ethylene glycol or propylene glycol, the hydroxyl molecular weight is apt to approximate the theoretical molecular weight, based on completeness of reaction, if oxypropylation is conducted slowly and at a comparatively low temperature, as described. In this instance, however, this does not seem to follow, as it is noted in the preceding table that at the point were the theoretical molecular weight is approximately 2,000, the hydroxyl molecular weight is only about one-half this amount. This generalization does not necessarily apply where there are more hydroxyls present, and in the present instance the results are somewhat peculiar when compared with simple dihy droxylated materials as described, or with phenols.

The fact that such pronounced variation takes place between hydroxyl molecular weight and theoretical molecular weight, based on completeness of reaction, has been subjected to examination and speculation, but no satisfactory rationale has been suggested.

One suggestion has been that one hydroxyl is lost by dehydration and that this ultimately causes a break in the molecule in such a way that two new hydroxyls are formed. This is shown after a fashion in a highly idealized manner in the following Way:

In the above formulas the large X obviously is not in tended to signify anything except the central part of a large molecule, whereas, as far as a speculative explanation is concerned, one need only consider the terminal radicals as shown. Such suggestion is of interest only because it may be a possible explanation of how an increase in hydroxyl value does take place which could be interpreted as a decrease in molecular weight. This matter is considered subsequently in Part 3. Formation of cyclic alkylene oxide polymers, if not reactive towards polycarboxy acids, presumably would have the effect of decreasing the apparent hydroxyl value.

The final products at the end of the oxypropylation step were somewhat viscous liquids, about as viscous as ordinary polypropylene glycols, with a dark amber tint. This color, of course, could be removed if desired by means of bleaching clays, filtering chars, or the like. The products were slightly alkaline due to the residual caustic soda. The residual basicity due to the catalyst would be the same if sodium methylate had been employed.

Needless to say, there is no complete conversion of propylene oxide into the desired hydroxylated compounds. This is indicated by the fact that the theoretical molecular weight, based on a statistical average, is greater than the molecular weight calculated by usual methods on basis of acetyl or hydroxyl value. This is true even in the case of a normal run of the kind noted previously. It is true also in regard to the oxypropylation of simple compounds, for instance, propylene glycol or ethylene glycol.

Actually, there is no completely satisfactory method for determining molecular weights of these types of compounds with a high degree of accuracy when the molecular. weights exceed 2,000. In some instances the acetyl value or hydroxyl value serves as satisfactorily as an index to the molecular weight as any other procedure, subject to the above limitations, and especially in the higher molecular weight range. If any difliculty is encountered in the manufacture of the esters, as described in Part 2, the stoichiometrical amount of acid or acid compound should be taken which corresponds to the indicated acetyl or hydroxyl value. This matter has been discussed in the literature and is a matter of common knowledge and requires no further elaboration.

In fact, it is illustrated by some of the examples appear? ing in the patent previously mentioned.

PART 2 As previously pointed out, the present invention is concerned with acidic esters obtained from the oxypropylated derivatives described in Part 1, preceding, and' polycarboxy acids, particularly tricarboxy acids like citric,

and dicarboxy acids such as adipic acid, phthalic acid, or

anhydride, succinic acid, diglycollic acid, sebacic acid, azelaic acid, aconitic acid, maleic acid, or anhydride, citraconic acid or anhydride, maleic acid or anhydride adducts, as obtained by the Diels-Alter reaction from products such as maleic anhydride, and cyclopentadiene. Such acids should be heat-stable so they are not decomposed during esterification. They may contain as many as 36 carbon atoms as, for example, the acids obtained by dimerization of unsaturated fatty acids, unsaturated monocarboxy fatty acids, or unsaturated monocarboxy acids molal ester, the anhydride, the acyl chloride, etc. How-- ever, for purpose of economy it is customary to use either the acid or the anhydride. A conventional procedure is employed. On a laboratory scale one can employ a resin pot of the kind described in U. S. Patent No. 2,499,370, dated March 7, 1950, to De Groote and Keiser, and particularly with one more opening to permit the use of a porous spreader if hydrochloric acid gas is used as a catalyst. Such device or absorption spreader consists of minute alundum thimbles which are connected to a gas tube. One can add a sulfonic acid such as paratoluene sulfonic acid as a catalyst. There is some objection to this because in some instances there is some evidence that this acid catalyst tends to decompose or rearrange heatoxypropylated compounds. It is particularly likely to do so if the esterification temperature is too high. In the case of polycarboxy acids such as diglycollic acid which is strongly acidic there is no need to add any catalyst. The use of hydrochloric acid gas has one advantage over paratoluene sulfonic acid and that is that at the endof the reaction it can be removed by flushing out With nitrogen, whereas there is no reasonably convenient means available of removing the paratoluene sulfonic acid or other sulfonic acid employed. If hydrochloric acid is employed one need only pass the gas through at an exceedingly slow rate so as to keep the reaction mass acidic. Only a trace of acid need be present. I have employed hydrochloric acid gas or the aqueous acid itself to eliminate the initial basic material. My preference, however, is to use no catalyst whatsoever and to insure complete dryness of the diol, as described in the final procedure just preceding Table 2.

The products obtained in Part 1, preceding, may contain a basic catalyst. As a general procedure, I have added an amount of half-concentrated hydrochloric acid considerably in excess of what is required to neutralize the residual catalyst. The mixture is shaken thoroughly and allowed to stand overnight. It is then filtered and refluxed with the xylene present until the water can be separated in a phase-separating trap. As soon as the product is substantially free from water the distillation stops. This preliminary step can be carried out in the flask to be used for esterification. If there is any further deposition of sodium chloride during the reflux stage, needless to say, a second filtration may be required. In any event, the neutral or slightly acidic solution of the oxypropylated derivatives described in Part 1 is then diluted further with suflicient Xylene, decalin, petroleum solvent, or the like, so that one has obtained approximately a 45 %65% solution. To this solution there is added a polycarboxylated reactant, as previously described, such as phthalic anhydride, succinic acid, or anhydride, diglycollic acid, etc. The mixture is refluxed until esterification is complete, as indicated by elimination of water or drop in carboxyl value. Needless to say, if one produces a half-ester from an anhydride such as phthalic anhydride, no water is 11 eliminated. However, if it-is obtained fronr diglycollic acid, for example, Water is eliminated. All-such procedures are conventional and have been so thoroughly described in the literature-that-further consideration will be limited to. a, few examples and a comprehensive table.

Other procedures foreliminating the basic residual catalyst, if any, can be employed. For example, the oxyalkylation can be conducted in absence of a solvent or the solvent removed after oxypropylation. Such oxypro' plation end-product can then be acidified with just enough concentrated hydrochloric acid to just neutralize the resid'ual basic catalyst. To this product one can then add a small amount of anhydrous sodiumsulfate (sufficient in quantityto take up any water that is present) and then subject the mass to centrifugal force so as to eliminate the hydrated sodium sulfate and probably the sodium chloride formed. The clear, somewhat viscous, strawcolored amber liquid so obtained may contain a small amount of sodium sulfate or sodium chloride, but in any event is perfectly acceptable for esterification in the manner described.

It is to be pointed-out that the products here described are not polyesters in the sense that there is aplurality of both diol-radicals and acid radicals; the product is characterized by having only one diol radical.

In'someinstances and, in fact, in many instances, I have found that in spite of the dehydration methods employed above, a mere trace of water still comes through, and that this mere trace of water certainly interferes with the acetyl or-hydroxyl value determination, at least when a number of conventional procedures are used and may retard esterification, particularly where there is no sulfonic acid or hydrochloric acid present as a catalyst. Therefore, I have preferred to use the following procedure: I have employed about 200 grams of the diol compound, as described in Part 1, preceding; I have added about 60 grams of benzene and refluxed this mixture in the glass resin pot, using a phase-separating trap, until the benzene carried out all the water present as water of solution or the equivalent.- Ordinarily this refluxing temperature is aptto be in the neighborhood of 130 C. to possibly 150 C. When allthis water or moisture has been removed! also withdraw approximately 20 grams, or a little less, benzene and'then add the required amount of the carboxy reactant and. also about 150 grams of a high-boilingaromatic petroleum solvent; These solvents are sold by' various-oil refineries and, as far as solvent effect goes, act as if they were almost completely aromatic in character. Typical distillation data in the particular type I ml., 200 C.

, 30 ml., 225" c.

12 have employed and found very satisfactory is the following:

I. B. P., 142 C. ml.,. 242 C. ml., 244 C. ml., 248 C. ml., 282 C. ml., 252 C. ml., 260 C. ml., 264 C. ml., 270 C.

10 ml., 209 C. 15 ml., 215 C. 20 ml., 216 C. 25 ml., 220 C.

35 ml., 230 C. 40 ml., 234 C. ml., 280 C. 45 ml., 237 C. ml., 307 C.

After this material is added refluxing is continued and,

1:) of course, is at a high temperature, to wit, about to.

C. If the carboxy reactant is an anhydride, needless should be eliminated at the above reaction temperature. If it is not eliminated, I simply separate out another 10 to 20 cc. of benzene by means of the phase-separating trap and thus raise the temperature to or C., or even to 200 C., if need be. My preference is not to go above 200 C.

25 The use of such solvent is extremely satisfactory, provided one does not attempt to remove the solvent subsequently, except by vacuum distillation, and provided there is no objection to a little residue. Actually, when these materials are used for a purpose, such as dernulsification, the solvent might just as well be allowed to remain. If the solvent is to be removed by distillation, and particularly vacuum distillation, then the high boiling aromatic petroleum solvent might well be replaced by some more expensive solvent, such as decalin or an 5 alkylated decalin which has a. rather definite or close. range boiling point. The removal of the solvent, of course, is purely a conventional procedure and requires no elaboration.

When starting with the high molal glycol, as herein :0 described, as one of the raw materials I have found that xylene by itself is practically or almost assatisfactory as other solvents or mixtures. Decalin also is suitable. Actually, at times there is some advantage in using a mixture of a high-boiling aromatic petroleum solvent and xylene in preparation of other typical examples of the kind herein described.

The data included in the subsequent tables, i. e., Tables 2 and 3, are self-explanatory and very complete and it is believed no further elaboration is necessary.

TABLE 2 Theo. hy- M01. wt. Amt. of Ex.N0. of Theo. mol Actual Amt. of Ex. No. of droxyl Based on polycar: acid. ester aggy 0 value of 1 353 3 actual g Polycmbmy reactant boxy react- H. H.V. ant (grs.)

3,090 36. 3 54. 7 2,050 205 Diglycolic acid 26. 8 3, 090 36. 3 54. 7 2, 050 205 Phthalic anhydride 29. 6 3,090 36. 3 54.7 2, 050 205 Maleic anhydride 19. 6 3, 090 36. 3 54. 7 2,050 205 Acom'tic acid 34. 8. 3, 090 36. 3 54. 7 2, 050 205 Citraconie anhydricle. 22. 4 3, 090 36. 3 54. 7 2, 050 205 23. 6 4,070 27. 6 49. 1 2, 289 229 26. 8 4, 070 27. 6 49. 1 2, 289 229 19. 6 4, 070 27. 6 49. 1 2, 289 229 29. 6 4,070 27. 6 49. 1 2, 289 229 Aconitic acid 34. 8 4, 070 27. 6 49. 1 2, 289 229 Citraconic anhydride. 22. 8 4, 070 27. 6 49. 1 2, 289 229 Succinic acid 23. 6 2, 920 38. 3 59. 6 1,885 188. 5 Diglycolic acid"-.. 26.8 2, 920 38. 3 59. 6 1, 885 188. 5 Phthalic anhydride 29. 6 2, 920 38. 3 59. 6 1, 885 188. 5 Maleic anhydride- 19. 6 2, 920 38. 3 59. 6 l, 885 188. 5 Citraconic anhydri 22. 4 2, 920 38. 3 59. 6 1, 885 188. 5 Aeonitic acid 34. 8 2, 920 38. 3 59. 6 1, 885 188. 5 23. 6 4, 630 24. 2 47. 6 2, 358 235. 8 Diglycolic aci 26. 8 4, 630 24. 2 47. 6 2, 358 235. 8 Phthalic anhydride. 29.6 4, 630 24. 2 47. 6 2, 358 235. 8 Maleic anhydride l9. 6 4, 630 24. 2 47. 6 2, 358 235. 8 Citraconic anhydridc. 22. 4 4, 630 24. 2 47. 6 2, 358 235. 8 Aconitic acid 34. 8 4, 630 24. 2 47. 6 2, 358 235. 8 Succinic acid 23. 6 3, 210 34. 9 56. 7 1, 975 197. 5 Diglycolic acid 26. 8 3, 210 34. 9 56. 7 1, 975 197. 5 Maleic anhydride 19. 6 3, 210 34. 9 56. 7 1, 975 197. 5 Phthalic anhydride- 29. 6 3, 210 34. 9 56. 7 1, 975 197. 5 Oitraconic anhydride 22. 4 3, 210 34. 9 56. 7 1, 975 197. 5 Aconitic acid 34. 8 3, 210 34. 9 56. 7 1, 975 197. 5 Succinic acid 23. 6 3, 270 34. 35 54. 6 2, 035 203. 5 Diglycolic acid. 26. 8 3, 270 34. 35 54. 6 2, 035 203. 5 Maleic acid 29. 6 3', 270 34. 35 54. 6 2, 035 203. 5 Phthalic anhydride. l9. 6 3, 270 34. 35 54. 6 2, 035 203. 5 Citraconic anhydride. 22. 4 3, 270 84. 35 54. 6 2, 035 203. 5v Aconitic acid. 34. 8 3, 270 34. 35 54. 6 2, 035 203'. 5 Succinic acid 23. 6

TABLE 3 Maximum Ex. No. Amt. esterifig Water of acid Solvent solvent cation g out ester (grs) t ng? (hm) (00.)

The procedure for manufacturing the esters has been illustrated by preceding examples. If for any reason reaction does not take place in a manner that is acceptable, attention should be directed to the following details:

(a) Recheck the hydroxyl or acetyl value of the oxypropylated high molal glycol as in Part 1, preceding;

(b) If the reaction does not proceed with reasonable speed, either raise the temperature indicated or else extend the period of time up to 12 or 16 hours if need be;

(c) If necessary, use /2 of paratoluene sulfomc acid, or some other acid, as a catalyst; and

(d) If the esterification does not produce a clear prod uct, a check should be made to see if an inorganic salt such a sodium chloride or sodium sulfate is not precipitating out. Such salt should be eliminated, at least for exploration experimentation, and can be removed by filtering.

Everything else being equal, as the size of the molecule increases and the reactive hydroxyl radical represents a smaller fraction of the entire molecule, more difiiculty is involved in obtaining complete esterificatlon.

Even under the most carefully controlled conditions of oxypropylation involving comparatively low temperatures and long time of reaction, there are formed certain compounds whose compositions are still obscure. Such side reaction products can contribute a substantial proportion of the final cogeneric reaction mixture. Various suggestions have been made as to the nature of these compounds, such as being cyclic polymers of propylene oxide, dehydration products with the appearance of a vinyl radical, or isomers of propylene oxide or derivatives thereof, i. e., of an aldehyde, ketone, or allyl alcohol. In some instances an attempt to react the stoichiometric amount of a polycarboxy acid with the oxypropylated derivative results in an excess of the carboxylated reactant, for the reason that apparently under conditions of reaction less reactive hydroxyl radicals are present than indicated by the hydroxyl value. Under such circumstances there is simply a residue of the carboxylic reactant which can be removed by filtration, or, if desired ,the esterification procedure can be repeated, using an appropriately reduced ratio of carboxylic reactant.

Even the determination of the hydroxyl value and conventional procedure leaves much to be desired, due either to the cogeneric materials previously referred to, or, for that matter, the presence of any inorganic salts or propylene oxide. Obviously this oxide should be eliminated.

The solvent employed, if any, can be removed from the finished ester by distillation, and particularly vacuum 14 distillation. The final products or liquids are generally from almost black or reddish-black to dark amber in color, and show moderate viscosity. They can be bleached with bleaching clays, filtering chars, and the like. However, for the purpose of demulsification or the like, color is not a factor and decolorization is not justified.

In the above instances I have permitted the solvents to remain present in the final reaction mass. In other instances I have followed the same procedure, using decalin or a mixture of decalin or benzene in the same manner and ultimately removed all the solvents by vacuum distillation.

PART 3 In the hereto appended claims the demulsifying agent is described as an ester obtained from a polyhydroxylated material prepared from the described diols. If one were concerned with a monohydroxylated material or a dihydroxylated material one might be able to write a formula which in essence would represent the particular product. However, in a more highly hydroxylated material the problem becomes increasingly more difficult for reasons which have already been indicated in connection with oxypropylation and which can be examined by merely considering for the moment a monohydroxylated material.

Oxyalkylation, particularly in any procedure which involves the introduction of repetitious ether linkages, i. e., excessive oxyalkylation, using, for example, ethylene oxide, propylene oxide, etc., runs into difliculties of at least two kinds; (a) formation of a cogeneric mixture rather than a single compound, and (b) excessive side reactions or the like. The former phase will be considered in the paragraphs following. As to the latter phase, see U. S. Patent No. 2,236,919 dated April 1, 1941, to Reynhart.

Oxypropylation involves the same sort of variations as appear in preparing high molal polypropylene glycols. Propylene glycol has a secondary alcoholic'radical and a primary alcohol radical. Obviously then polypropylene glycols could be obtained, at least theoretically, in which two secondary alcoholic groups are united or a secondary alcohol group is united to a primary alcohol group, etherization being involved, of course, in each instance. Needless to say, the same situation applies when one has oxypropylated polyhydric materials having 4 or more hydroxyls, or the obvious equivalent.

Usually no effort is made to differentiate between oxypropylation taking place, for example, at the primary alcohol radical or the secondary alcohol radical. Actually, when such products are obtained, such as a high molal propylene glycol or the products obtained in the manner herein described one does not obtain a single derivative such as HO(RO)nH or -(RO)nH in which n has one and only one value, for instance, 14, 15 or 16. or the like. Rather, one obtains a cogeneric mixture of closely related or touching homologues. These materials invariablyl have high molecular weights, and cannot be separated from one another by any known procedure, without decomposition. The proportion of such mixture represents the contribution of the various individual members of the mixture. On a statistical basis, of course, 21 can be appropriately specified. For practical purposes one need only consider the oxypropylation of a monohydric alcohol because in essence this is substantially the mechanism involved. Even in such instances where one is concerned with a monohydric reactant one cannot draw a single formula and say that by following such procedure one can readily obtain 80% or or of such compound. However, in the case of at least monohydric initial reactants one can readily draw the formulas of a large number of compounds which appear in some of the probable mixtures or can be prepared as components and mixtures which are manufactured conventionally.

Simply by way of illustration reference is made to U. S. Patent No. 2,549,434, dated April 17, 1951, to De Groote, Wirtel and Pettingill.

However, momentarily referring again to a monohydric initial reactant it is obvious that if one selects any such simple hydroxylated compound and subjects such compound to oxyalkylation, such as oxyethylation, or oxypropylation, it becomes apparent that one is really producing a polymer of the alkylene oxide except for the terminal group. This is particularly true where the amount of oxide added is comparatively large, for in- "stance,1.:l0,:Q0;80;?2101:=50...units. 01f such compound is subjected to;.oxyethylationasmas to introducew304nnitst-bf mthylenezoxidegit :is wellt'knowntthanonedoes not obtain a zsingle: constituent whichpfor thensake of. :convenience, ":may be: indicatedzas fiR0(C2I-Ii0 )soOH. lnsteadgsrone obtains .a cogenerictmixture: of :closely =related:homologues :in a which: the! formula; unay: be :shown 1 as: the. following: -RO'(.C2H4O)1LH,: whereinnz; asrfarsas the :statisticaln'aver- :ageagoesd is .3 0,: but- :the e'individual. members." present. .in isignificant': amount may'Wary from-instances where: n .has: .awaluehofzli .andrperhapsiless, :to; a. pointawhere r n may represent 35 or more. (Such mixture is, as stated, a cogeneric closely related series of touching homologous xcompounds. Considerable:investigation' has? been made rim" regard I0 the distribution: icurves fun 1 linear Polymers. iAttentioriais directed;toithe article' entitled *Tundamental -Rrinciples loft .Condens'ation: Polymerization, 'by" Flory, whichmppearedzinGhemicabkeviews; volume 39, No. l, .pa'gel37.

i-Unfortunatcly,.1as':has beenz'pointed out by Flory. and zotheninvestigalors; there: is'tno :satisfactoryrmethod; based -onf.=either: experimentalizorrr mathematical examination; of indicating 1theexact proportionrof the various members of touching: :hom'olo'gousr' series' which 1 appear in. -co generic condensatiomproducts of:thekind/described. i'This-rneans 1 .that .fromthetpractical standpoint; i; e.;?.the.ability toideascribeihow itOIHEIkC zthe product .under: consideration and :how: torrepeatusuch: production time a after. time without :diific'ulty, it: is necessary :to resort to somerotheramethod eofzdescriptiony or felse .considerrthe'valuetofin, infor- -mulas: .such asxthose WhiCht'ihave: appeared. previously and #whichtappear in the claims; as'representing bothrin- .dividual constituentsiin= which n'hasa single definite value, and also with the understanding that n represents the ;average statistical value based on'the: assumption of com- .ple'tenessof-reaction.

hlS'Il'l'lfiYd'J illustrated as follows: Assume thatint'any :par'ticular' example therm'olal ratio ofpropyl'ene. oxide per th-ydroxyliis". 15::to .l. iIn-asgene'ric formula 215 10 l could :bei l0,..20,- or some other. amount and/indicated by'n. .Referring .to .this :specific :case actually one 'obtains prod- .ucts:?in *which rt probablyivariesfrom -10 .to.-20,"perhaps :even: further. ;The'. average value, :however, is l5, .astsuming; as previouslyvst-ated, that therreaction is.com-

plete. The product :shown-"by: the formula. .isperhaps best idescribed also in; ttermsr of rmethod. of manufacture. xzltlvbecomeskobvious that when carboxylic acidic esters "are mprepared from "such high :molal 1 molecular weight nnaterials that v the: ultimate :esterification;:product' must,

:in! turngbeza:.cogcnericxmixture. 1 Likewise; .it:is.-obvious :thatzthe contribution .toxthe total molecular weight made byrithezipol-ycarboxy reactanLis small. :Thus, onemight expectithat the effectiveness-hither demulsifierinrthe form ot fi'the acacidic -rfractional :ester uwould :1 be comparable to 1:.the westerified hydroxylatcd material. :enough,:in practically: every :instance the product .is .dis- .tinctlyrbetter, and 'in the-"majority. of instances much more effective.

' PART 4 "Conventional"demulsifying agents employed in the treatment-of oil field emulsions areused as su'chg or after dilution with any suitable's'olvent; such as waterypetro- -leum' hydrocarbons; such as benzene, toluene,- xylene, =tar acid oil, cresol, anthracene oil; etc. Alcohols, particularly "aliphatic alcohols, such asmethyl alcohol; ethyl alcohol, "denatured alcohol,"propyl alcohol, butyl alcohol; hexyl -alcohol, octyl alcohol, etc., may be-employed as diluents. Miscellaneous solvents-such aspine: oil,"ca'rbon .tetrochloiride; sulfur. dioxide extractwobtained irnthe "refining: of petroleum, etc.; maybe employedas diluents. :Similarly,

theznnaterial: or rnaterials. employed as thezdemulsifying Remarkably be treated, in anyof the various apparatus'now generally used to resolve or bre'ak petroleum emulsions withz=a :chemical reagentpthe above procedure beingusedalone or in' corhbination with ':other demulsifyingprocedure,

.such as the electrical dehydration process.

One ;type of .procedure'is to accumulate a volume of emulsified oil in a tank and conduct abatch treatment type of demulsificationzprocedure to recover clean oil. in this procedure-the emulsion is admixed withthe demulsifier, for example by agitatingthe tank of emulsion and slowly dripping demulsifieri into the emulsion. In some cases mixing is achieved byheating the emulsion while "dripping ain' the demulsifier, depending upon-the convection currents in the: emulsion to produce satisfactory admixture. "In a third modification ofthis type of treatment, a circulating pump withdraws emulsion from, e.- g., .the' bottom of the tank, and reintroduces it into -the top. of the tank, the demulsifier being added, for ex- :ample, vatthe suction side of said circulating pump.

1 In a second type of treating procedure, the demulsifier is introduced intoithe well fiuidsat the well-head or at some point between the well-head and the final oil'storage tank, by means of an adjustable proportioning mechanism "or propor'tioningcpump. Ordinarily the flow of fluids through the subsequent lines and fittings suflices to produce the 'desired degree of mixing of demulsifier and aemulsion,.= although .in 'someiinstances additional mixing devicesmay be introducedrintothe flowsystem. In this general procedure, the system 'may include various =mechanical J devices for withdrawing free water, separating entrained water, oraccomplishinggquiescent settling of the chemicalized emulsion. Heating devices'may likewise :be. incorporatedJinnany of the :treating procedures described herein.

-.A.:third type of application .(down-the-holey'of de- .mulsi-fier:to' emulsion isto introducefrhe' demulsifier either periodically or continuously in dilutedor undiluted form into tthe1Well=and tozallowzit .to come tor-the surface with the well fluids, and :then :toEflow-the chemic'alized emulsion: :through' any- 5 desirable surface equipment, such as :employedzin -.the :otherutreatingz. procedures. This 'particular-atype of application .iswdecidedly useful whemthe demulsifier is used in connection with acidificationi of calcareousaoibbearingstrata; especially if suspended in -or: dissolved :inzthe: acid :employed for acidification.

=:In allcrcases, it will be apparentfrom "the foregoing description,tl the:=broad PIOCeSSwCOHSiStS. simply .in rintroducingaatrelativelyt small: proportion: of demulsifier into 21: relatively large 1 proportion of emulsion, admixing the chemicalra'andi.emulsion :either through 'natural' flow or .through special.apparatusywithror without :the applicaitionzofi? heat, and allowing thetmiXture to. stand quiescent until the. undesirable-Water:content of. the emulsion sepa- .rates1andrsettles from themass.

The' foll0Wingiis1 a'itypical installation.

A reservoir to hold the demulsifier of'the kind. described tt'diluteds-on undiluted) isyplacedfatthe Well-head where the efiiuent liquids .leavei the-well. This reser voir or container,--which may vary-from 5 gallons to 50 gallons for convenience, is c0noectedito a=-proportioning "pump which inje'cts 'ft-hedemuls ifier drop-wise into the fluids =1eaving* the well. Such'chemicalizedfiuids-pass through the flowlineinto a settling tank. "The settlingtank consistspf a tankiof any convenient size; for-instance, one which willlh'old. amounts ofr'fluid produced in 4 to 24 hours .(500. barrels. 10.12000. barrels. capacity), and in whichithere ista perpendicular. conduit .fromthe top of the. tankato'almost-fthe very bottom solas to permit the incoming fluidstopass from the top=of the-settling tank to. the bottom,-.--sothatrsuch'incoming. flUidSfd01l1Ot-di$- turb stratification-1whichtakes placezduring the: course of .demulsi-fication. Tiler-settling tank has two outlets, one ibeing 'b'elow the water'devel to' 'drain' ofi the -waterresion as free water, the other being an oil outlet at the top to permit the passage of dehydrated oil to a second tank, being a storage tank, which holds pipeline or dehydrated oil. If desired, the conduit or pipe which serves to carry the fluids from the well to the settling tank may include a section of pipe with baffles to serve as a mixer, to insure thorough distribution of the demulsifier throughout the fluids, or a heater for raising the temperature of the fluids to some convenient temperature, for instance, 120 to 160 F., or both heater and mixer.

Dernulsification procedure is started by simply setting the pump so as to feed a comparatively large ratio of demulsifier, for instance, 1:5,000. As soon as a complete break or satisfactory demulsification is obtained, the pump is regulated until experience shows that the amount of demulsifier being added is just suflicient to produce clean or dehydrated oil. The amount being fed at such stage is usually 1:10,000, 1215,000, 1:20,000, or the like. In many instances the oxyalkylated products herein specified as demulsifiers can be conveniently used without dilution. However, as previously noted, they may be diluted as desired with any suitable solvent. For instance, by mixing 75 parts by weight of an oxyalkylated derivative, for example, the product of Example 712 with 15 6 parts by Weight of xylene and 10 parts by weight of isopropyl alcohol, an excellent demulsifier is obtained. Selection of the solvent will vary, depending upon the solubility characteristics of the oxyalkylated product, and of course will be dictated in part by economic considerations, i. e., cost.

As noted above, the products herein described may be used not only in diluted form, but also may be used admixed with some other chemical demulsifier. A mixture which illustrates such combination is the following:

oxyalkylated derivative, for example, the product of Example 7b, 20%;

A cyclohexylamine salt of a polypropylated naphthalene monosulfonic acid, 24%;

An ammonium salt of a polypropylated naphthalene monosulfonic acid, 24%;

A sodium salt of oil-soluble mahogany petroleum sulfonic acid, 12%;

A high-boiling aromatic petroleum solvent, 15%;

Isopropyl alcohol,

The above proportions are all weight percents.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is:

1. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsifier including synthetic hydrophile products; said synthetic hydrophile products being characterized by the following formula:

in which R' represents a saturated alkyl radical containing at least 5 and not more than 18 carbon atoms, and R" represents a saturated alkyl radical containing not more than 18 carbon atoms; 11 and n represent whole numbers which, when added together, equal a sum varying from 15 to 80; n is a whole number not over 2, and R is the carbon-linked radical of a polycarboxy acid selected from the group consisting of acyclic and isocyclic polycarboxy acids.

COOH

in which n" has its previous significance; with the final proviso that the parent dihydroxylated compound prior to esterification be water-insoluble.

2. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsifier including synthetic hydrophile products; said synthetic hydrophile products being characterized by the following formula:

in which R and R" represent saturated unsubstituted alkyl groups having straight chains containing from 7 to 18 carbon atoms; n and n represent whole numbers which, when added together, equal a sum varying from 15 to 80; n" is a whole number not over 2, and R is the carbon-linked radical of a polycarboxy acid selected from the group consisting of acyclic and isocyclic polycarboxy acids OOOH in which n" has its previous significance; with the final proviso that the parent dihydroxylated compound prior to esterification be water-insoluble.

3. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsifier including synthetic hydrophile products; said synthetic hydrophile products being characterized by the following formula:

in which R and R" represent the same saturated unsubstituted alkyl groups having straight chains containing from 7 to 18 carbon atoms; n and 11' represent whole numbers which, when added together, equal a sum varying from 15 to 80; n" is a whole number not over 2, and R is the carbon-linked radical of a polycarboxy acid selected from the group consisting of acyclic and isocyclic polycarboxy acids OOOH in which n" has its previous significance; with the final proviso that the parent dihydroxylated compound prior to esterification be water-insoluble.

4. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsifier including synthetic hydrophile products; said synthetic hydrophile products being characterized by the following formula:

in which R and R" represent the same saturated unsubstituted alkyl groups having straight chains containing from 7 to 18 carbon atoms; n and n represent Whole numbers which, when added together, equal a sum varying from 15 to 80; n" is a whole number not over 2, and R is the carbon-linked radical of a polycarboxy acid selected from the group consisting of acyclic and isocyclic polycarboxy acids COOH in which n" has its previous significance; with the final proviso that the parent dihydroxylated compound prior to esterification be water-insoluble and xylene-soluble.

5. A process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsifier including synthetic hydro-.

i 9 phile product's; sa-id synthetic hydrophile'products"being; characterized by the followingformulat in which n has its previous significance; said polycarboxy acid. having. not oven-8. carbon atoms; with the final proviso that thep'a'rent dihydroxylated compound prior to esterification be water insoluble. and, xyleneesoluble'.

6. A process for hrealking petroleum emulsions of the water-inrfdil type characterize'd'by subjecting. the emulsion to the action of, demul'sifier, including synthetic hydrophile products; said synthetic hydrophile products being characterized lay the following formula:

in which R 'and- R" represent thesamesaturated un substituted alkyl groups having straight chains containing fromZ to 18 carbon atoms; n and n represent Whole numbers which, when added together, equal asumv-arw ing from 15 to and Ris the carbon-linked radical of V a dicarboxy acid selected from the group consistingyof acyclic and isocyclic dicarboxy acids ooorr said dicarboxy acid having not over 8 carbon atoms; and with the further proviso that the parent dihydroxylated compound prior to esterification be Water-insoluble and Xylene-soluble.

7. The process of claim 6 wherein the dicarb oxyacid is phthalic acid.

8. The process of claim 6 wherein the dicarboxy acid is mal'eic acid.

9. The process of claim 6 wherein the dicarboxy acid is succinic acid.

10. The process of claim 6 wherein the dicarboxy acid is citraconic acid.

11. The process of claim 6 wherein the dicarboxy acid is diglycollic acid.

References Cited in the file of this patent UNITED STATES. PATENTS Number Name Date 2,562,878 Blair Aug. 7, 1951 2,597,204 Todd et 'al May'ZO, 1952 

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-OIL TYPE CHARACTERIZED BY SUBJECTNG THE EMULSION TO THE ACTION OF A DEMULSIFIER INCLUDING SYNTHETIC HYDROPHILE PRODUCTS; SAID SYNTHETIC HYDROPHILE PRODUCTS BEING CHARACTERIZED BY THE FOLLOWING FORMULA: 